Erectable structures

ABSTRACT

AN ERECTABLE STRUCTURE FORMED BY ONE OR MORE UNITS HAVING AT LEAST TWO CONNECTED SUPPORT MEMBERS. EACH OF THE SUPPORT MEMBERS IS IN TURN FORMED BY A PLURALITY OF FOLDABLE PANELS. IN THE COLLAPSED OR FOLDED CONDITION THE STRUCTURE OCCUPIES A HEIGHT EQUAL SUBSTANTIALLY TO THE SUM OF THE THICKNESSES OF THE TOTAL NUMBER OF PANELS FORMING THE SUPPORT MEMBER ON ONE SIDE OF THE STRUCTURE AND EACH SUPPORT MEMBER OCCUPIES AN AREA SUBSTANTIALLY EQUAL TO THE AREA OF ONE OF ITS FOLDED PANELS. WHEN UNFOLDED OR DEPLOYED, THE PANELS OF EACH SUPPORT MEMBER ARE EXTENDED AND LOCK TOGETHER TO FORM A STRUCTURE WHICH IS SUBSTANTIALLY RIGID ALONG ITS LONGITUDINAL AXIS AND IN A DIRECTION TRANSVERSE THERETO. THE ERECTED STRUCTURE ALSO HAS A RELATIVELY LARGE SURFACE AREA WHICH IS SUBSTANTIALLY EQUAL TO THE SUM OF THE AREAS OF THE INDIVIDUAL PANELS FORMING THE SUPPORT MEMBERS.

Sept. 21, 1971 v T.G.BERRY ERECTABLE STRUCTURES 4 Sheets-Sheet 1 Original Filed Feb. 15, 1965 GAS SOURCE INVENTOR THOMAS G. BERRY BY $2M; )floa ATTORNEYS Sept. 21, 1971 BERRY 3,605,719

ERECTABLE STRUCTURES Original Filed Feb. 15. 1965 v 4 sheets-Sheet 3 INVENTOR. THQMAS e. BERRY ATTORNEYS Sept. 21, 1971 -BERRY 3,605,719

I ERECTABLE'STRUCTURES Original Filed Feb. 15, 1965 '4 sheets'sheet 5 INVENTOR THOMAS. G. BERRY ATTORNEYS Sept. 21, 1971 T. G. BERRY ERECTABLE STRUCTURES 4 Sheets-Sheet 4 Original Filed Feb. 15. 1965 FIG. 7A

FIG. 7B

INVENTOR. THOMAS G. BERRY ATTORNEYS United States Patent Office 3,606,719 Patented Sept. 21, 1971 3,606,719 ERECTABLE STRUCTURES Thomas G. Berry, Washington, D.C., assignor to Fairchild Hiller Corporation, Hagerstown, Md. Continuation of application Ser. No. 432,780, Feb. 15, 1965. This application July 12, 1968, Ser. No. 752,436 Int. Cl. E04b 1/34, 12/18, 7/16 US. Cl. 52632 Claims ABSTRACT OF THE DISCLOSURE An erectable structure formed by one or more units having at least two connected support members. Each of the support members is in turn formed by a plurality of foldable panels. In the collapsed or folded condition the structure occupies a height equal substantially to the sum of the thicknesses of the total number of panels forming the support member on one side of the structure and each support member occupies an area substantially equal to the area of one of its folded panels. When unfolded or deployed, the panels of each support member are eX- tended and lock together to form a structure which is substantially rigid along its longitudinal axis and in a direction transverse thereto. The erected structure also has a relatively large surface area which is substantially equal to the sum of the areas of the individual panels forming the support members.

This application is a continuation of copending application Ser. No. 432,780 filed Feb. 15, 1965, now abandoned.

This invention relates to erectable or deployable structures and more particularly to a structure which is erected from a folded or collapsed condition occupying a relatively small volume and surface area to a deployed condition having a relatively large surface area and considerable structurable strength.

In a preferred embodiment of the invention the support members of each unit are arranged to close upon each other so that the erected structure encloses a volume. If desired, a top and bottom member may be provided for each unit of the structure and the support members for the unit connected thereto. Upon deployment, the panels of the support members extend from their folded condition moving the top and bottom members out from each other. In the fully deployed condition the top and bottom members give additional stability to the structure in a direction transverse to its longitudinal axis.

The structures of the present invention are erectable by various mechanical and pneumatic systems. In one improvement disclosed herein, a pneumatic inflatable bag is utilized while another embodiment uses a spring mechanism.

It is therefore an object of the present invention to provide various forms of erectable structures.

Another object is to provide a structure which occupies a small volume in its folded condition and erects to provide a large surface area.

An additional object is to provide an erectable structure formed by a plurality of connected support members each of which includes a number of folded panels.

Still a further object is to provide an erectable structure formed by a plurality of units each having top, bottom, and side members, the latter being formed by a plurality of panels which are folded in the minimum volume condition of the structure, and extended when the structure is fully erected.

An additional object is to provide a structure capable of being erected by inflation by a pneumatic source.

Another object of the invention is to provide an erectsame.

Other objects and advantages of the present invention will become more apparent upon reference to the following specification and annexed drawings in which:

FIG. 1 is a perspective view of an erectable structure made in accordance with the present invention showing the details and general operating principles thereof;

FIG. 2 is a perspective view of another embodiment of structure utilizing a pneumatic erecting mechanism;

FIG. 2A is a perspective view of another embodiment of structure utilizing a different form of pneumatic erecting mechanism;

FIGS. 3A, 3B and 3C are sectional views of an embodiment of structure using a spring erecting apparatus showing various stages of deployment;

FIG. 4 is a view, taken partly in section, looking into the drawing of FIGS. 3A-3C and showing portions of the spring mechanism for erecting the structure of FIG. 3, with the structure being in the semi-deployed condition;

FIG. 5 is a view, taken partly in section, looking along lines 55 of FIG. 3C, showing the structure in a fully deployed condition;

FIGS. 6A, 6B and 6C are perspective views of anothe embodiment of the invention; and

FIGS. 7A and 7B are perspective views of a T-bar type erectable structure showing various stages of deployment.

FIG. 1 shows in semi-deployed, or semi-erected, condition one embodiment of erectable structure illustrating the general operating principles of the present invention. The structure includes a number of units 10-1, 10-2, 10-3, etc., of similar construction. As many of these units 10 may be provided as needed in accordance with the surface area of the structure desired. Since all of the units are of similar construction, only one is described in detail.

As shown, unit 10-1 has a top member 12 and a bottom member 14. These two members, or their equivalent in the form of a common member, between two adjacent units 10, are provided for each unit. Corresponding ends of the top and bottom members of each unit are joined together by a respective support or side member 16 whose ends are hingably connected to the ends of members 12 and 14 and/or to the adjacent support member. Each support member 16 is shown as having two panels 17 and 18 which are foldable, for example by means of a hinge, about a line 19. Of course, more than two foldable panels may be provided for each member 16. Since many suitable mechanisms are available in the art for the connection of members 12, 14 and 16, for folding the panels of member 16 and for locking panels 17 and 18 to prevent them from folding in a direction opposite to the one intended, these are not shown in detail.

The top and bottom members 12 and 14 of the structure of FIG. 1 are illustratively shown as being generally rectangular. Four support members 16-1, 16-2, 163 and 164 are provided, these members and their respective panels 17 and 18 also are generally rectangular with the panels of support members 16-1 and 163 being wider than those of members 16-2 and 164. Of course, members 12 and 14 may be square or of any other quadrangular form. In all of these cases the support members 16 would still be rectangular, or square, depending upon the aspect ratio (width to height) desired for them.

Top and bottom members of shapes other than a quadrangle also may be used with these having three or more straight sides, i.e., the members are regular or irregular polygons. In this case the foldable support members joining corresponding sides of the top and bottom polygonal members are rectangular or square, depending upon the regularity of the polygon and/or the desired aspect ratio. When erected, the support members of this type of structure close upon each other to enclose a volume. This provides a considerable degree of strength for the fully deployed structure. In the embodiment of structure shown in FIG. 1, the panels of the wider side members 16-1 and 16-3 fold outwardly while the panels of the narrower side members 16-2 and 16-4 are constructed to fold inwardly with respect to the top and bottom members 12 and 14. The reverse arrangement may be used, if desired, so that the wider panels fold inwardly and the shorter panels outwardly. In either case, the height or depth of the structure in the folded condition is substantially equal to the sum of the thicknesses of all the folded panels 17 and 18 on any one side of the structure. Each support member 16 when fully folded also occupies only an area equal to the area of one of its panels.

Each of the members 12, 14, and 16 may be formed of any suitable rigid material, forexample plastic, metal, etc. They may be solid sheets, sheets partially cut-away to reduce overall weight, or of a sectionalized construction such as the familiar honeycomb configuration used in the formation of aircraft components such as wings. Members 12, 14 and 16 also may be formed of a semi-rigid material such as an expanded cellular polyethylene plastic, for example Styrofoam. The selection of the material and the size of the various members, of course, depends upon the application for which the structure is to be used.

If desired, the various units -1, 10-2, 10-3, etc., may be formed separately and then a respective top member 12 of one unit, for example 10-2 fastened to a respective bottom member 14 of the adjacent unit, for example 10-1. Also, if desired, the various units can be formed at the same time so that one of the members, such as member 14, serves as the common top and bottom member for the support members of two adjacent units, such as units 10-1 and 10-2.

In operation, the structure of FIG. 1 is initially collapsed so that all of the support members 16 have their panels 17 and 18 folded about their respective fold lines 19. In this condition, the narrower support members 16-2 and 16-4 are folded inwardly between adjacent top and bottom members 12 and 14 of the same unit while the wider support members 16-1 and 16-3 are folded outwardly. Thus, the structure occupies an area equal to the sum of the areas of a member 12 or 14 plus twice the area of one of the panels 17 or 18 of a member 16-1 or 16-3. The height of the folded structure is equal to the sum of the thicknesses of the folded panels of any one support member 16 plus the thicknesses of members 12 and 14 if these contribute to the overall height. In the fully erected condition all the members 16 are substantially fiat and extend to their maximum height between the top and bottom members 12 and 14 of a unit. In this embodiment members 12 and 14 provide greater stability for the fully deployed structure, particularly in a direction transverse to the structures longitudinal axis.

In FIG. 1, if the support members 16-1 and 16-3 are folded inwardly and members 16-2 and 16-4 folded outwardly, then the overall area of the structure in the collapsed condition is reduced by the difference in area between the panels 16 and 17 of members 16-1 and 16-2.

FIG. 2 shows one form of erecting mechanism for the structures of the present invention. Here the structure is somewhat different from that of FIG. 1 and is formed by a base plate 21 to which is hingably fastened the support members 26-1 through 26-4 of unit 20-1. Each support member has two panels 27 and 28 which fold about a line 29. In this embodiment, the members corresponding to the top and bottom members 12 and 14 of FIG. 1 are omitted so that each unit 20-1, 20-2, 20-3 and 20-4 has its support members hingably connected to the support members of the next unit, and joined together at the corners thereof by any suitable means such as the hinge fasteners 31. The upper unit 20-4 has a top member 33 to which the upper ends of the side panels 26 for that unit are hingably connected.

An inflatable bag 35 is located within the structure and the bottom of this bag is fastened to the base plate I 21, either on the inside or the outside of the structure, in

communication with an inlet 36. The bag may be of any suitable material, such as stretchable rubber, plastic, etc. Also connected to the inlet 36 is a conduit 38 which is connected to the output of a suitable source of fluid 40, such as a container of compressed gas or a gas generator. The gas produced by the source 40 may be of any suitable type depending upon the environment in which the structure is to be used. For example, it could be compressed air, oxygen, helium, etc., or any other suitable gas. A liquid, such as water or oil may also be used or the bag may be filled with an expanded cellular plastic such as Styrofoam. Where the latter is used, the fully deployed structure would have high flotation properties and, also, puncture of the bag would not cause the structure to collapse.

In the folded condition of the embodiment of FIG. 2 all of the panels of support members 26 are folded outwardly about their respective fold lines 29 to provide space for bag 35. Thus, the total area of the structure in the collapsed condition is equal to the sum of the area of the base plate 21 plus the areas of one panel of each support member 26.

When it is desired to erect the structure the gas source 40 is energized to inflate bag 35. As the bag inflates it pushes out against the top plate 33 thereby unfolding the panels of the support members 26. The volume and shape of the bag 35 is selected so that when it is fully inflated the support members are completely extended to their maximum height. Locking devices (not shown) are preferably provided to hold the support members flat once they are fully deployed. Depending upon the pressure of the gas in the bag and the external pressure on the environment in which the structure is utilized, the structure of FIG. 2 can provide a fair amount of rigidity, even without locking devices.

FIG. 2A shows another embodiment of the invention similar to that of FIG. 2. Here, however, top and/or bottom members, similar to members 12 and 14 of FIG. 1, are used between each of the units 20-1 through 20-4. As before, the top and bottom members for each unit can either be separate or else one member can serve as a common top and bottom member for two units. Considering that a common member 14 is used between two units, the lower ends of the panels 26 for unit 20-1 are hingably connected to base plate 21 while the upper ends are hingably connected to member 14-11. The lower ends of the side panel for the unit 20-2 are also hingably connected to member 14-1 and the upper ends of these panels are hingably connected to the next member $14-2, and so forth for the remainder of the structure. In this arrangement the fasteners 31 of FIG. 2 are not necessary.

Each of the units 20-1 through 20-4 has a respective inflatable bag -1 through 45-4. The lower end of each bag is connected to the bottom member of the unit while the upper end of each bag is connected to the top member. An inlet 36 is provided in each of the members 14 and 21 so that the gas from the source 40 can communicate with the various bags 45-1 through 45-4.

The structure of FIG. 2A functions in a manner similar to that of FIG. 2. Here, the members 14 between each unit provide added strength for the structure and permit each of the units 20 to have its own inflatable bag. In both embodiments of FIGS. 2 and 2A, the bags can be made of a self-sealing material. Also, the same filling materials can be used as described for FIG. 2.

The structures described in both FIGS. 2 and 2A are generally square or rectangular in shape and have four support members 26. As before, any polygonal shaped structure can be formed and this also applies to the structure of FIG. 2, where there are no top or bottom members between units.

FIGS. 3A-3C, 4 and 5 show another embodiment of the invention utilizing a mechanical erecting system. Here, the structure is covered by a shroud 52 which covers a well 54 containing a pair of cable reels 56 and a pair of friction or centrifugal brakes 58. Only one cable reel and brake are shown but the others are identical. The well is mounted on the surface 60 of a building or vehicle, the latter of which may either be moving or stationary.

As is described in greater detail below, the panels 17 and 18 of the support members 16 of structure 50 are spring loaded and, unless restrained, will expand to fully deploy the structure. Four cables 57 provide the restraining force. Each cable reel '56 pays out a pair of cables over pulleys 61 mounted on the wall of well 54. The upper end of each cable is attached at 53 to the shroud 52 which serves as the top member for the outermost unit of the structure 50 or as a cover for that member. After the shroud '52 is released from the well and the brakes 58 are also reelased, springs on each of the units erect the structure.

FIG. 3A shows structure 50 in a fully folded condition with the shroud 52 seated on a flange 64 in the well. FIG. 33 illustrates the semi-deployed condition of the structure, there being some tension exerted on the cables by the brake, while FIG. 30 shows the structure fully erected. Once the structure has been fully erected, the shroud may be discarded, if desired, providing the upper unit of the structure has a top member.

In the structure 50 of FIG. 3, all of the panels of the support members 16 fold outwardly. A hinge assembly 70 is located at each corner junction of the support members of two adjacent units. The hinge assembly 70 connects together the panels 17 and 18 of the same numbered support member of the two adjacent units (e.g. panel 117 of support member 16-1 of unit 50-1 to panel ;18 of support member 16-1 of unit 15-2) as well as connecting the corners of adjoining support members of each unit together (e.g. members 16-1 and 16-2; 16-2 and 16-3; 1'6-3 and 16-4; and 16-4 and 16-1 of the same unit).

FIG. 4 is a portion of the structure of FIG. 3 in semideployed condition showing the details of the spring-loaded hinges and particularly depicting the connection of adjacent panels 17 and 18 of the support members of two of the units. FIG. shows additional details of the hinge assembly 70 connecting adjoining support members of the same unit, the structure here being in a fully deployed condition.

The hinge assembly 70 of FIGS. 4 and 5 is shown used on panels 17 and 18 formed of conventional honeycomb construction having a skin on each side thereof. FIG. 4 shows the corner junction of the adjacent panels 17 and 18 for each of the support member 16-2 and 16-3 of units 50-1 and 50-2. A corner of each panel at the junction is recessed and a fitting 73 is placed in the recess and connected to the panel. Each fitting 73 has a collar 74 or 75 formed with a bore to accommodate an L-shaped hinge pin 77. When the support members are assembled, the collar 74 or 75 of a fitting on one panel lies adjacent the collar of the adjacent panel to which connection is to be made to permit the hinge pin to pass through both collars. A pocket 78 is formed in each fitting 73 and amend of the hinge pin extends therein. Each arm of the hinge pin holds a spring 79 between collar 74 and a nut 80. Each spring 80 has ends 81 and 82 which respectively engage the adjacent side panels 17 and 18 of the two units. The tension of the spring 80 is selected so that it has sufiicient strength to outwardly expand the two adjacent panels 17 and 18 of the two adjacent units.

As can be seen in FIGS. 4 and 5, the hinge assembly 70 connects support members \16-1 and 16-3 of both units 50-1 and 50-2 together as well as providing for the expansion of adjacent panels 17 and 18 of the support members 16-1 and 16-1 and 16-3 and 16-3 of the two units. A similar hinge assembly 70 is located at each corner junction of the panels of every two units. The hinges for the folds 19 of the panels of each support memare not shown since any suitable type of hinge may be used. If desired, a spring-loaded hinge can be used at the fold 19 between panels 17 and 18 of a support member. This further aids in deployment of the structure. A hinge assembly similar to assembly 70 may be used at the junction of the lowermost unit 50-1 to the well 54 and the junction of the uppermost unit to the shroud 52. Here, one end of each spring would act against a fixed surface.

When the brake 58 is released each hinge assembly 70 moves the panels apart from the folded condition. This can be more readily visualized by referring to FIG. 2 and considering that it is the spring action at the corner fasteners 31 which causes the structure to deploy.

The spring mechanism described in FIGS. 3A-3C, 4 and 5, may be used to erect any shape structure where the adjoining support members thereof are to be connected together.

FIGS. 6A6C show another embodiment of the invention where three support members 106-1, 106-2 and 106-3 are used in conjunction with a larger member 107. Here, as seen in FIGS. 6A and 6B the panels of members 106-1, 106-2 and 107 fold outwardly to provide a space therebetween for the panels of member 106-3 which fold inwardly between the panels of the other three members. A hinge connects the lower two corners of the panel at each end of member 106-2 to the adjacent corner of the corresponding end panel of members 1011-1 and 101-3. Similarly, a hinge 111 connects the upper, inner corners of the panel at each end of members 106-1 and 106-3 to adjacent points on the corresponding end panels of member 107. Hinges 110 and 111 permit the end panels of members 106-1 and 106-3 to pivot with respect to the connected panels of member 107, as the structure is deployed, and also permit the end panels of member 106-2 to pivot with respect to the connected panels of members 106-1 and 106-3.

A hinge assembly 112, similar to hinge assembly 70 described previously, is located at the corner junctions of members 106-1; 106-2 and 106-2; 106-3. As the panels of members 106-\1, 106-2 and 106-3 unfold, they also unfold the panels of member 107 whose end panels are connected to the end panels of members 106-1 and 106-3 by hinges 111. If desired, hinges 110 may also be springloaded so that the end panels of members 106-1, 106-2 and 106-3 may be more easily deployed. The hinges i113 connecting the panels of member 107 which are originally in line with hinges 111 at the junction of the upper inner corners of members 106-1 and 106-3 and the inner fold line of two adjacent panels of member 107 when the structure is folded also may be spring-loaded to facilitate deployment. However this is not necessary due to the connection of the outer ends of the end panels of members 106-1 and 106-3 to the outer ends of the end panels of member 107, since deployment of the panels of members 106 automatically deploy the panels of member 107. The same is true for the hinges at the outer fold lines of the panels of member 107.

The structure of FIGS. 6A6C packages most efiiciently with an aspect ratio of three, as seen in FIG. 6A. Here, the length of a panel of member 107 is equal to the combined widths of the corresponding three panels of the three members 106. If only the panels of member 107 are to provide the surface area which is to be utilized, then the panels of the other members may be of a trusswork construction to reduce the overall weight of the structure. The same holds true with respect to the panels of the other embodiments of the invention disclosed and claimed herein so the term panel should be construed accordingly where used.

FIGS. 7A and 7B show another embodiment of the invention in which a slightly dilferent folding pattern is utilized to form a structure having the shape of a T-bar. Here, a support member 86 has a plurality of panels 86-1 through 86-8 which are connected to each other by hinges 87 to permit the panels to fully fold together in accordian fashion. FIG. 7A shows the semi-deployed condition of 7 the structure. A bridging stem support member 90 formed by panels 90-1, 90-2, 90-3, 90-4 and 905 connected together by hinges 913 is provided and the outer end of each of panels 90-1 and 90-5 is connected to the respective outer end of panels 86-1 and 86-8 by a respective hinge 92. As shown in FIG. 7A, the panels 90 also fold in an accordian fashion. Panels 90-1 and 90-5 are as long as the single panels 86-1 and 86-6 are wide while panels 90-2 through 90-4 are as wide as two of the panels 86. A number of locking devices 95 are provided, either on the support 86 or the stem support 90 to connect panels 90-2, 90-3 and 90-4 to the panels of support member 86 when the structure is fully deployed. The locking device may be a spring-latch, nuts and bolts, magnetic catch, etc.

To erect the structure of FIGS. 7A and 7B, the panels 86 are preferably driven apart by the unfolding of the panels of stem support 90*. Therefore, hinges 93 are preferably spring-loaded to deploy the panels 90. Since only panels 90-1 and 90-5 are initially connected by hinges 9.2 to the end panels 86-1 and 86-8, unfolding the stem member panels 90 cause the panels 86 to unfold. When the panels of both support members 86 and 90 are fully extended, the locking devices 95 are actuated. Panels 86 are now prevented from folding in either direction due to the bridging support member which is connected thereto at hinges 92 and at locking devices 95. Panels 90 also cannot bend due to the actuation of the locking devices 95 and they are generally perpendicular to the panels 86.

In the type of structure shown in FIGS. 7A and 7B the stem support member 90 is preferably made of a strong material to give the structure adequate strength. For most efficient packaging and use of fewest hinges and locking devices, the length of each stern support panel 90 other than panels 90-1 and 90-5, is made twice as long as the width of one of the panels 86. Of course each panel 90 can be made to bridge more than two panels 86. The height of the stem member 90 is determined by the stiffness requirements of the system.

The erectable structures of the present invention have many uses. For example, they can be used on a space vehicle to provide a large surface area to hold a number of solar cells or other types of radiation receiving or radiation transmitting devices. In this application the structure in its folded condition occupies a small volume before deployment, such as during launch and the initial stages of flight, and when erected provides a large surface area of the detectors or transmitters used. Additional uses include those of structural members, such as in building a foot bridge, pontoon bridge, etc., Where the structure can be readily carted to the work area in a folded form and then deployed. In this case additional trusswork type reinforcing members can be used, if desired, after the structure is erected.

While preferred embodiments of the invention have been described above, it will be understood that these are illustrative only, and the invention is limited solely by the appended claims.

What is claimed is:

1. An erectable panel beam structure comprising first, second, third and fourth support members, each of said support members formed by at least one pair of panels, means for folding the panels of the panel pairs of each support member with respect to each other, means connecting the respective end panels of all four support members together to unfold all of the panels of the support memberssimultaneously when one panel of one support member is unfolded, said last named means connecting said panels so that the panels of said first and second support members are generally parallel to each other when unfolded with the panels of said third support member when unfolded connected across the panels of said first and second support members to define a generally U-shaped structure, said connecting means also making the panels of said fourth support member overlying the panels of said first and second support members across the open end of said U-shaped structure, the panels of said third and fourth support members folding in the same direction and the panels of said first and second members folding in directions opposite to each other which are generally perpendicular to the direction of folding of the panels of said third and fourth support members.

2. An erectable panel beam structure as in claim 1 wherein the structure when folded comprises respective stacks of panels of the first, second and third support members lying side-by-side adjacent a common side of the stack of panels of said fourth support member.

3. An erectable panel beam structure as in claim 2 wherein the width of the stack of folded panels of said fourth support member is substantially equal to the sum of the Widths of the stacks of folded panels of said first, second and third support members.

4. An erectable panel beam structure comprising a plurality of first and a plurality of second support members, respective hinge means for connecting said first support members together to form a first element and for connecting said second support means together to form a second element, each of said support members of said elements formed by at least two panels which fold with respect to each other, the panels of said support members of said elements when unfolded being generally trans verse to one another to form a structure with one element supporting the other, and means connecting the support members of said first and second elements to unfold their panels together, the length of each of the end panels of the end support members of one element being substantially equal to the Width of the corresponding end panels of the end support members of the other element and the length of the intermediate panels of the support members of said one element being substantially equal to the width of two of the intermediate panels of the support members of said other element.

*5. An erectable structure as in claim 4 wherein said elements when unfolded form a generally T-shaped structure.

References Cited UNITED STATES PATENTS 3,091,816 6/1963 Wetzel 5271 3,153,798 10/ 1964 Drevitson 1472 3,256,440 6/ 1966 Stark 52-2 JOHN E. MURTAGH, Primary Examiner US. Cl. X.R. 

